The use of microbes to degrade a variety of noxious wastes to environmentally-acceptable products is an ongoing project in our society. Numerous successes in cleaning the environment by such microbial means has given an impetus to the research. The benefits of such microbial cleansing systems is considered to be great in terms of providing a cleaner, and safer, environment, at an acceptable cost. Illustrations of some recent microbial discoveries in this are are found in issued patents. Some of these patents are as follows:
U.S. Pat. No. 4,477,570 concerns the use of Pseudomonas cepacia var. niagarous to decompose aromatic halogen-containing organic wastes.
U.S. Pat. No. 4,483,923 claims Pseudomonas fluorescens 3P, which is used to remove non-ionic surface active agents and detergents from wastewater.
U.S. Pat. No. 4,490,471 discloses the use of various Pseudomonads for purification of aqueous solutions by degradation of lower alkanols, lower alkanoates, monosaccharides, disaccharides and a variety of methylammonium compounds.
U.S. Pat. No. 4,492,756 relates to the use of a microbe from the genus Hyphomicrobium to degrade compounds which contain methyl groups in aqueous solutions.
U.S. Pat. No. 4,493,895 results from a divisional application wherein the parent application matured into U.S. Pat. No. 4,477,570, described above.
U.S. Pat. No. 4,508,824 uses Pseudomonas putida and Pseudomonas aeruginosa to degrade various hydrocarbons.
U.S. Pat. No. 4,511,657 concerns a microbial culture system using the microbes described in U.S. Pat. No. 4,493,895, listed above.
U.S. Pat. No. 4,521,515 claims a novel Pseudomonas bacterium to degrade hydrocarbons such as may be found in an oil spill.
U.S. Pat. No. 4,535,061 claims a specific strain of Pseudomonas cepacia and a mixed culture of Pseudomonas and Arthrobacter which are useful to degrade various polychlorinated biphenyls.
U.S. Pat. No. 4,554,075 concerns the use of the white-rot fungus (Phanerochaete chrysosporium) for the degradation of chloro-organics.
Several bacteria have been found to degrade chlorinated hydrocarbons. One organism, identified as Pseudomonas cepacia var. niagarous, is disclosed in U.S. Pat. No. 4,477,570, referred to above. This organism was reported to degrade a variety of chlorinated toluenes and benzoic acids.
T. Leisinger and his co-workers were the first to describe aerobic biodegradation of ethylene dichloride (EDC). Initially, these researchers were unable to isolate a pure culture of the bacteria (Stucki, G., Brunner, W., Staub, D. and Leisinger, T. [1981 ] In Microbial Degradation of Xenobiotics and Recalcitrant Compounds, Leisinger, T. Look, A. M., Hutter R. and Nuesch, J. eds Academic Press, London, pp 131-137), but they then proceeded to obtain such a culture (Stucki, G., Krebser, U. and Leisinger, T. [1983] Experentia 39:1271-1273). This organism was not identified by name and was designated DE2. It could not grow on a solid medium such as agar plates.
A second bacterium which degrades EDC was described by Janssen et al. and was identified by them as Xanthobacter autotrophicus (Janssen, D. B., Scheper, A., Dijkhuizen, L. and Witholt, B. [1985] Applied and Environ. Microbiol. 49:673-677). Thus, bacterial identifications which were carried out by Colaruotolo et al. (U.S. Pat. No. 4,477,570 and U.S. Pat. No. 4,493,895) and Janssen et al. supra, resulted in different bacterial strains. They also differ from the bacterium of the subject invention, which was identified as Alcaligenes denitrificans ss. denitrificans by the American Type Culture Collection (ATTC).
The organism DE2, which was isolatd by Stucki et al. (Stucki et al. 1983, supra), is not available for comparative studies. It seems, however, to differ from both A. denitrificans and X. autotrophicus by its vitamin dependency and its inability to grow on solid media. The former two bacteria grow readily on different compositions of solid media and do not require any vitamins for growth.
The above patents and publications are evidence of the active research being conducted to find microbial systems to degrade a variety of compounds. Though much has been done in this area, there still are literally hundreds of compounds which cannot be degraded by known microbial means. Though the degradation of compounds to cleanse the environment is finding significant support from environmental groups, there is also a need to discover new microbial processes to degrade compounds to useful intermediates or end products. Throughout these efforts to find new microbes, it is clearly evident that there is no predictability as to whether any partiular microbe might have desirable degradative capabilities. Basically, the science is still at the empirical stage.